We revisit the Gross-Neveu model with N fermion flavors in
1+1 dimensions and compute its phase diagram at finite
temperature and chemical potential in the large-N limit.
To this end, we double the number of fermion degrees of
freedom in a specific way which allows us to detect
inhomogeneous phases in an efficient manner. We show
analytically that this "fermion doubling trick" predicts
correctly the position of the boundary between the
chirally symmetric phase and the phase with broken chiral
symmetry. Most importantly, we find that the emergence of
an inhomogeneous ground state is predicted correctly. We
critically analyze our approach based on this trick and
discuss its applicability to other theories, such as
fermionic models in higher dimensions, where it may be
used to guide the search for inhomogeneous phases.